The deadline to file petitions for the Aug. 28 primaries is 5 p.m. Wednesday. The general election will be held Nov. 6.

One other Democrat, civil rights activist and immigration attorney Deedra Abboud, has submitted signatures in the race for the seat being vacated by Republican Jeff Flake, who is not seeking reelection.

The seat is key in the Democrats’ efforts to take control of the Senate, which the GOP holds by a 51-49 margin (including two Independents who caucus with the Democrats).

Sinema has been serving in the U.S. House since 2012. Besides name recognition and a political track record, she has the financial backing to make a push to become Arizona’s first Democratic senator since Dennis DeConcini retired in 1995 after his third term.

According to Federal Election Commission financial reports through the first quarter of 2018, Sinema had raised more than $8.2 million and had more than $6.8 million on hand.

That was more than the top three Republican primary candidates combined. The total of cash on hand for Martha McSally, Kelli Ward and Joe Arpaio was just under half of Sinema’s war chest.